If you have bought a used slow cooker or you have had your slow cooker for a number of years and aren’t sure if your slow cooker is cooking at the correct temperature, you can test it.
Fill your slow cooker with 2 quarts of lukewarm water. Cover with the lid and cook on low for 8 hours. Have a thermometer ready (a meat thermometer will work) after the 8 hours is up, life the lid and immediately place the thermometer in the water.
If the temperature is 185 degrees, your slow cooker is cooking perfectly. If it is under 185 degrees, chances are that you could be risking having your food undercooked or susceptible to harmful bacteria growth. If it is higher than 185 degrees, you will have to shorten your cooking time or your meals could be overdone.